KR20030013933A - Driving method of liquid crystal display panel - Google Patents

Abstract

PURPOSE: A driving method of a liquid crystal display panel is provided, which reduces user's fatigue when images having different resolutions are displayed on one screen. CONSTITUTION: A microcomputer judges whether an image signal is received(53). The device judges whether input image signals have the same resolution(54). If input image signals have the same resolution, the brightness is maintained without adjustment(55). If input image signals have different resolutions, the brightness of an input image signal having a relatively low resolution is maintained without adjustment, while the brightness of an input image signal having a relatively high resolution is increased with a predetermined value according to a resolution(59).

Description

Driving Method of Liquid Crystal Display Panel

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display panel, and more particularly, to a method of driving a liquid crystal display panel to reduce user fatigue when images having different resolutions are displayed on one screen.

In general, a liquid crystal display panel has an inherent resolution corresponding to the number of pixels to be integrated, and the larger the size of the liquid crystal display panel, the higher the resolution. In addition, in order to display high quality images, manufacturers of liquid crystal display panels have different resolutions by increasing pixel integration ratios in liquid crystal panels even among liquid crystal display devices of the same size.

In the environment of a personal computer or the like including the liquid crystal display device, the standard of the above-described video signals and control signals was set by the Video Electronics Standard Association (VESA) in February 1989 together with the resolution.

Standards for displays used primarily in the commercial display industry today are generally Dos Mode (640 X 350, 640 X 400, 720 X 400), VGA (640 X 480), SVGA (800 X 600), and XGA (1024 X). 768), SXGA (1280 X 1024), and UXGA (1600 X 1200).

Since the resolution of the liquid crystal display panel is fixed by the number of arranged pixels, the system requires an image signal and its control signals that match the resolution of the liquid crystal panel. Therefore, the system converts video signals and control signals corresponding to various display standards into video signals and control signals according to the resolution and display standard of the liquid crystal display panel using a scaler chip and supplies them to the liquid crystal display panel.

1 is a block diagram of a general liquid crystal display device.

Referring to FIG. 1, a liquid crystal display device supplies a data driver 18 and a gate driver 20 for supplying a data signal and a scanning signal to a liquid crystal panel, and supplies a data signal and a control signal to the data driver 18. The gate driver 20 includes a timing controller 12 for supplying a control signal, an interface unit 10 for supplying control signals and data signals to the timing controller 12, and a gate high voltage for the gate driver 20. Vgh) and a voltage converter 14 for supplying a common voltage Vcom to the driving devices.

First, the interface 10 receives data (RGB Data) and control signals (for example, an input clock, a horizontal synchronization signal, a vertical synchronization signal, and a data enable signal) input from a driving system such as a personal computer. ). Mainly, LVDS (Low Voltage Differential Signal) interface and TTL interface are used for data and control signal transmission with driving system. In addition, the interface functions are collected and used together with the timing controller 12 in a single chip.

The timing controller 12 uses a control signal input through the interface unit 10 to use a data driver 18 including a plurality of drive ICs (not shown) and a gate driver composed of a plurality of gate drive ICs (not shown). A control signal for driving 20 is generated. In addition, data input from the interface unit 10 is transmitted to the data driver 18.

The data driver 18 selects reference voltages according to the input data in response to control signals input from the timing controller 12, converts the reference voltages into analog image signals, and supplies them to the liquid crystal panel 22.

The gate driver 20 turns on / off the gate terminals of thin film transistors (“TFTs”) arranged on the liquid crystal panel 22 in response to control signals input from the timing controller 12. (on / off) control, and the analog image signals supplied from the data driver 18 are applied to each pixel connected to each thin film transistor.

The voltage converter 14 supplies a gate high voltage Vgh for driving the thin film transistor in the liquid crystal panel 22 to the gate driver 20, and generates and supplies a common electrode voltage Vcom of the liquid crystal panel 22. . In addition, reference voltages are set by the producer based on the transmittance-voltage characteristics of the panel.

2 shows displaying a screen having two resolutions on the liquid crystal panel 22.

In FIG. 2, the liquid crystal panel 22 typically uses a Windows operating system. Such Windows OS is set to express UXGA level data, and when a document is edited using a word processor among various computer programs, graphics and pictures are inserted during document editing.

The liquid crystal panel 22 includes a first screen 11 capable of realizing a full screen with SVGA resolution and a change in pixel for a certain area of the full screen, that is, data information of high resolution is displayed. It may be divided into a second screen 21 of UXGA level. For example, when texts that can be implemented at low resolution are displayed on the first screen 11, data information such as graphics and pictures having high resolution is displayed on the second screen 21. Done. In this case, the luminance of the first screen 11 and the second screen 21 according to the data voltage supplied to the liquid crystal panel 22 is shown in FIG. 3.

Referring to FIG. 3, the liquid crystal panel 22 is supplied with the same data voltage applied to the first screen 11 and the second screen 21 when the data signal is applied from a data signal supply unit (not shown). Accordingly, the luminance of the data signals of the first screen 11 and the second screen 21 are the same. This has the same luminance regardless of the data signal having high resolution or the data signal having low resolution.

Accordingly, the data voltage applied to the first screen 11 including the SVGA resolution data and the second screen 21 including the UXGA grade data higher than the first screen 21 are supplied. By applying the same data voltage, the second screen 21 on which data information such as graphics and photographs is displayed is not clear. The luminance of the first screen 11 composed of SVGA-class data and the second screen 21 composed of UXGA-class data is approximately 150 nits. Here, nit is the amount of light emitted from the unit area to the unit solid angle. Cathode ray tubes, for example, have a maximum of 300 nits and average about 230 nits.

As such, since the first screen 11 and the second screen 21 in one screen have the same luminance distribution, the image quality of the second screen 21 requiring high resolution is degraded. This focuses attention on the graphic or photo rather than the general text, which increases eye fatigue.

4 illustrates displaying two screens 30 and 40 having different resolutions on another conventional liquid crystal panel 22.

Referring to FIG. 4, the liquid crystal panel 22 may be supplied with a first screen 30 capable of realizing a full screen at SVGA resolution and a pixel having a high resolution, which is changed and supplied for each pixel in a partial region of the full screen. The information may be divided into an XGA-class second screen 40 on which information is displayed. For example, when texts that can be implemented at low resolution are displayed on the first screen 30, data information such as graphics and photographs having a high resolution is displayed on the second screen 40. do.

In this case, since the luminance of the first screen 30 and the second screen 40 according to the data voltage supplied to the liquid crystal panel 22 is supplied in the same manner as in FIG. 3, the data signals of the two screens 30 and 40 are different. The luminance of has the same brightness.

Accordingly, the voltage applied to the data of the first screen 30 including the SVGA resolution data of the liquid crystal panel 22 and the data of the XGA resolution higher than the first screen 30 are configured. Since the data voltages applied to the data of the second screen 40 are the same, the second screen 40 having a high resolution is not clear. This is because the luminance of the first screen 30 having the SVGA grade and the second screen 40 having the XGA grade is approximately equal to 150 nits. As such, the eyes of the first screen 30 and the second screen 40 have the same brightness, and the eyes are focused on a graphic or a picture such as the second screen 40 rather than the general text of the first screen 30. Will increase.

Therefore, when displaying a high definition screen and a screen having a lower resolution at the same time in one screen of the liquid crystal panel 22, the luminance of the high definition screen requires higher luminance than a screen having a low resolution.

Accordingly, an object of the present invention is to provide a method of driving a liquid crystal display panel to reduce fatigue of a user when images having different resolutions are displayed on one screen.

1 is a view schematically showing a conventional liquid crystal display device.

2 is a view showing simultaneous display on two screens of a conventional liquid crystal display panel;

3 is a graph showing luminance according to a data voltage applied to a conventional liquid crystal display panel.

4 is a diagram illustrating displaying two screens simultaneously on a conventional liquid crystal display panel;

FIG. 5 is a view illustrating displaying two screens simultaneously on a liquid crystal display panel according to the present invention; FIG.

6 is a graph illustrating luminance according to data voltages applied to a liquid crystal display panel according to an exemplary embodiment of the present invention.

7 is a view showing displaying two screens simultaneously on the liquid crystal display panel according to the present invention;

8 to 10 are flowcharts showing an operation procedure of a liquid crystal display panel driving method according to an exemplary embodiment of the present invention.

<Explanation of symbols for main parts of drawing>

10: interface unit 12: timing controller

14: voltage converter 18: data driver

20: gate driver 22, 52: liquid crystal panel

11, 21, 30, 40, 50, 60, 70, 80: screen

53: image input determination unit 54: resolution determination unit

56: luminance satisfaction determination unit 57: user command determination unit

58: brightness control unit

In order to achieve the above object, the driving method of the liquid crystal display panel according to the present invention comprises the steps of determining the resolution of the video signal input to the liquid crystal display panel, detecting the video signal having a different resolution, and a video signal having a different resolution Adjusting the luminance of video signals having different resolutions so that the luminance difference appears in screen areas having different resolutions when is displayed on the same screen.

In the method of driving a liquid crystal display panel according to the present invention, detecting the image signals having different resolutions may include detecting a main screen having a low resolution and detecting a sub screen having a high resolution.

Other objects and features of the present invention in addition to the above objects will be apparent from the description of the embodiments with reference to the accompanying drawings.

Hereinafter, exemplary embodiments of the present invention will be described with reference to FIGS. 5 to 10.

Referring to FIG. 5, the liquid crystal panel 52 according to the present invention typically uses a window operating system. The Windows OS is set up to represent UXGA-class data, and when editing a document using a word processor among several computer programs, graphics and photos are inserted during document editing.

The liquid crystal panel 52 is provided with a first screen 50 capable of realizing a full screen composed of SVGA-class data, and is supplied in a different resolution for each pixel in a partial area of the full screen, that is, high resolution data information. It can be divided into the second screen 60 of the UXGA class is displayed. For example, when texts that can be implemented at low resolution are displayed on the first screen 50, data information such as graphics and photographs having a high resolution is displayed on the second screen 60. do. In this case, the luminance of the first screen 50 and the second screen 60 according to the data voltage supplied to the liquid crystal panel 52 is shown in FIG. 6.

Referring to FIG. 6, the data signal supply unit (not shown) recognizes the resolution of the screen when the data signal is applied and supplies data voltages to the first and second screens 50 and 60 of the liquid crystal panel 52 according to the resolution. In this case, a data voltage having a luminance of 0 to 200 nits is supplied to the first screen 50, and a data voltage having a luminance of 0 to 300 nits is supplied to the second screen 60. The data voltage supplied to the second screen 60 is selected by the user and has one level of the data voltage Z higher than the data voltage supplied to the first screen 50. Therefore, the maximum brightness of the screen having a high resolution is relatively brighter than the maximum brightness of the screen having a low resolution.

As a result, the luminance of the second screen 60 with the data using the UXGA-class resolution is higher than that of the luminance applied to the first screen 50 with the data using the SVGA-class resolution. The video signals of 60 appear brighter than the video signals of the first screen 50.

Therefore, in a screen that requires a high definition on one screen and a screen that does not, the eye fatigue is reduced by increasing the luminance of the required screen to brighten the high resolution screen.

7 illustrates displaying two screens having different resolutions on a liquid crystal display panel according to the present invention.

Referring to FIG. 7, the liquid crystal panel 52 may be supplied with a first screen 70 capable of realizing a full screen having data using SVGA resolution, and for each pixel in some areas of the full screen. The second screen 80 of the XGA class displaying high resolution data information may be divided. For example, when texts that can be implemented at low resolution are displayed on the first screen 70, data information such as graphics and photographs having a high resolution is displayed on the second screen 80. do. In this case, by supplying different data voltages supplied to the first screen 70 and the second screen 80 as shown in FIG. 6, the luminance of the data signal for each screen 70 and 80 has a different value. .

Accordingly, the voltage is applied to the first screen 70 composed of SVGA resolution data and supplied to the second screen 80 composed of data having XGA resolution higher than the first screen 70. The luminance is increased by supplying a high data voltage. By increasing the luminance of the second screen 80 having such a high resolution, the second screen 80 appears brighter than the first screen 70 so that it appears clearly.

As such, the luminance appearing according to the data voltage supplied to the liquid crystal panel 52 is operated in the same order as in FIG. 8.

In FIG. 8, the video input determination unit 53 determines whether the video signal is input in the microcomputer (not shown). (Step 1)

The input video signal is determined by the resolution determining unit 54 to determine a difference in resolution with respect to the video signal. (Second stage)

If it is determined that the video signal input from the resolution determining unit 54 has the same resolution, the luminance is maintained by the luminance maintaining unit 55 as it is. However, when the resolution is different with respect to the video signal, the brightness of the video signal having a low resolution is maintained by the brightness controller 59 while the brightness of the video signal having the high resolution is set to a value Z according to the resolution. Is increased accordingly. For example, assuming that the resolution of a video signal having a low resolution is SVGA level and that the resolution of a video signal having a high resolution is XGA or UXGA level, the data voltage of the set luminance Z of the high resolution is The XGA and UXGA level screens are set higher than the SVGA level. (Step 3)

In this way, by determining whether the resolution of the input video signal is the same and increasing the brightness of the video signal having a high resolution, the brightness of the video signal having the high resolution is brighter than the video signal having the low resolution. For example, if the first screen 50 is text and the second screen 60 is a graphic or a photo having a high resolution, the second screen 60 to which data information of high resolution is supplied has a low resolution. It becomes brighter than the first screen 50 to which data information is supplied.

Therefore, in a screen which requires a high definition on one screen and a screen that does not, the eye fatigue is reduced by increasing the luminance of the required screen to brighten the high resolution screen.

9 is a flowchart illustrating an operation procedure of a liquid crystal display panel driving method according to a second embodiment of the present invention.

In FIG. 9, in the microcomputer (not shown), the video input determining unit 53 determines whether or not the video signal is input. (Step 1)

The input video signal is determined by the resolution determining unit 54 to determine a difference in resolution with respect to the video signal. (Second stage)

If it is determined that the video signal input from the resolution determining unit 54 has the same resolution, the luminance is maintained by the luminance maintaining unit 55 as it is. However, when the resolution is different with respect to the video signal, the brightness of the video signal having a low resolution is maintained by the brightness controller 59 while the brightness of the video signal having the high resolution is set according to the resolution. Is increased accordingly. For example, assuming that the resolution of a video signal having a low resolution is SVGA level and that the resolution of a video signal having a high resolution is XGA or UXGA level, the data voltage of the set luminance Z of the high resolution is XGA and UXGA levels are set higher than SVGA levels. (Step 3)

Since the high resolution with increased brightness may have different satisfaction levels according to the user, the brightness satisfaction determination unit 56 determines the satisfaction level by the user's command for the brightness.

If there is no user command for the brightness, the increased brightness is maintained as it is. However, when the brightness value increased by the user's command is not satisfied, the data voltage is adjusted to increase or decrease the brightness. At this time, the user repeatedly adjusts until the brightness value is satisfied by increasing or decreasing the brightness value. (Step 4)

In this way, by determining whether the resolution of the input video signal is the same and increasing the luminance of the high resolution video signal, the high resolution video signal is brighter than the low resolution video signal. For example, if the first screen 50 is text and the second screen 60 is a graphic or a photo having a high resolution, the second screen 60 having a high resolution is larger than the first screen 50. It becomes brighter.

10 is a flowchart illustrating an operating procedure of a liquid crystal display panel driving method according to a third embodiment of the present invention.

In FIG. 10, the video input determination unit 53 determines whether the video signal is input in the microcomputer (not shown). (Step 1)

The input video signal is determined by the resolution determining unit 54 to determine a difference in resolution with respect to the video signal. (Second stage)

If it is determined that the video signal input from the resolution determining unit 54 has the same resolution, the luminance is maintained by the first luminance maintaining unit 55 as it is. However, when the resolution is different for the video signal, the user command decision unit 57 receives a command for adjusting the luminance value by the user. At this time, when there is no user command for luminance adjustment, the luminance is maintained by the second luminance maintaining unit 61 as it is. In contrast, when there is a user command for brightness control, the brightness is adjusted by the brightness controller 58. (Step 4)

The brightness controller 58 increases the brightness of a video signal having a high resolution or decreases the brightness of a video signal having a low resolution according to a user's command. Accordingly, the video signal having a high resolution and a low resolution Any one of the video signals will appear brighter. (Step 5)

For example, if the first screen 50 is text and the second screen 60 is a graphic or a photo having a high resolution, the second screen 60 having a high resolution is larger than the first screen 50. It becomes brighter.

Therefore, in a screen which requires a high definition on one screen and a screen that does not, the eye fatigue is reduced by increasing the luminance of the required screen to brighten the high resolution screen.

As described above, the method of driving the liquid crystal display panel according to the present invention increases the luminance of a screen requiring a high definition in one screen than a screen that does not need a high definition so that a high definition screen becomes relatively brighter than a screen that does not need a high definition. Effective display of the screen can minimize eye strain. In addition, power consumption may be reduced by supplying different data voltages to the liquid crystal panel.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the technical spirit of the present invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined by the claims.

Claims (4)

In a driving method of a liquid crystal display panel having a predetermined resolution, Determining a resolution of an image signal input to the liquid crystal display panel; Detecting video signals having different resolutions; And adjusting the luminance of the image signals having different resolutions so that the luminance difference appears in screen regions having different resolutions when the image signals having different resolutions are displayed on the same screen. The method of claim 1, Detecting image signals having different resolutions Detecting a main screen having a low resolution; And detecting a sub-screen having high resolution. The method of claim 2, And increasing the luminance of the sub-screen. The method of claim 1, And the brightness can be selected and adjusted by a user.